The present invention relates to a method and apparatus for storage of sheets which consist of paper or the like. More particularly, the invention relates to improvements in a method and apparatus for temporarily storing sheets between the convolutions of a flexible band which is wound onto a rotary core.
It is already known to store successive sheets of a stream of partially overlapping or non-overlapping sheets between the convolutions of a flexible band which is wound onto the core of a reel or the like. The sheets are fed onto the upper side of that portion of the band which is about to be converted into the outermost convolution on the core of the reel, and such sheets are held against slippage in that they are confined between two neighboring convolutions. As a rule, the band is relatively wide so as to guarantee that it engages substantial portions of neighboring sheets. This is considered necessary in order to ensure that the sheets which are temporarily stored between the convolutions of the band cannot move relative to each other, i.e., that they can be removed from temporary storage in a predetermined relationship with reference to one another, namely, in orientations in which they are ready for admission to the next processing station, e.g., into a gathering machine or the like. The cost of a relatively wide band is substantial because the band must meet a number of requirements with a high or very high degree of accuracy. Moreover, the bulk of a relatively wide band is pronounced, the same as the bulk of convolutions and of confined paper sheets on the core of the reel. It is necessary to ensure that the compactness of the convoluted band match or closely approximate an optimum value, i.e., that the band be subjected to a predetermined tensional stress which is a prerequisite for proper retention of stored sheets. Tensioning of a relatively wide and heavy band necessitates the exertion of a pronounced force, the provision of a sturdy frame for the parts of the apparatus, and the use of large prime mover means for advancing the band lengthwise.